SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '518b0b48f03c4b2d595e6c9dd44053c142154bb7f0f94ee13568a2d15469c3f7' 
  AND token = '9GjUd6bKm9zP169rIOz/JK8T+KygysqglnN9pInDV24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}